Regulatory Assets and Liabilities (Regulatory Balancing Accounts) (Details) - Southern California Edison - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Regulatory balancing accounts | Energy resource recovery account
Regulatory Assets and Liabilities
Net liability	$ (112)	$ 1,028
Regulatory balancing accounts | New system generation balancing account
Regulatory Assets and Liabilities
Net liability	(71)	35
Refunds of excess revenue | Significant Components
Regulatory Assets and Liabilities
Net liability	(1,283)	(331)
Refunds of excess revenue | Public purpose programs and energy efficiency programs
Regulatory Assets and Liabilities
Net liability	(754)	(874)
Refunds of excess revenue | Base rate recovery balancing account
Regulatory Assets and Liabilities
Net liability	(79)	(5)
Refunds of excess revenue | Greenhouse gas auction revenue
Regulatory Assets and Liabilities
Net liability	(142)	(182)
Refunds of excess revenue | FERC balancing accounts
Regulatory Assets and Liabilities
Net liability	16	(32)
Refunds of excess revenue | Generator settlements
Regulatory Assets and Liabilities
Net liability	(3)	(197)
Refunds of excess revenue | Other
Regulatory Assets and Liabilities
Net liability	$ (138)	$ (104)